There are several commercially available adhesives with sufficient optical clarity for use in optical applications such as those involving an optical fiber bonded to another optical fiber. Many of these optically clear adhesives, however, have a high coefficient of thermal expansion. That is, when subjected to varying temperatures, the optical fibers can move relative to each other resulting in a loss in the transmission efficiency.
There are several commercially available adhesives that have a low coefficient of thermal expansion. Many of these adhesives having a low coefficient of thermal expansion are filled with conventional fillers, which tend to increase the haze and decrease the transparency of the adhesive. These adhesives are not optically clear and are not suitable for many optical applications.